Remember that time I told you Alaskan mosquitoes didn’t carry disease?

It’s a standard source of conversation among clients and guides in the arctic. “Are there diseases you can catch from the mosquitoes?” My answer has always been a simple: “Nope.” However, it turns out there are actually two different viruses, closely related, that can be transmitted from mosquitoes to humans in Alaska: Snowshoe Hare Virus and the Jamestown Canyon Virus.

These two are closely related arboviruses in a group known as the California Serogroup. Arboviruses, despite the arboreal-sounding name have nothing to do with trees. Rather the name is a combination of arthropod and borne, thus arbovirus. The California Serogroup, of which these are a part, is a group of closely related arboviruses that include scary-sounding bugs like California encephalitis and Lacrosse encephalitis.

Fortunately, these aren’t really all that scary.

Snowshoe hares are actually just one of a number of hosts for the Snowshoe Hare virus, and are not likely to be the primary reservoir (the host where the virus hangs out between eruptions in other species). It’s been found in a mess of critters including rodents, carnivores, ungulates, and even birds. And yes, in humans.

Jamestown Canyon Virus has received more attention, but not much. This bug seems to be closely tied to ungulates. In the arctic, I think we can safely assume that caribou and moose are important hosts and reservoirs for the virus.

Neither of these two viruses seem to show any symptoms in wildlife, rather, they just hang out in the animal’s system, reproducing in moderate, non-damaging numbers. They are dispersed when a mosquito bites an infected host, and carries the virus elsewhere. That’s when humans enter the equation.

But we don’t enter it very much, or very often. These viruses seem to be cyclical, appearing and disappearing from the environment in booms and busts. During the up-cycles, humans can be bitten by an infected mosquito and receive a dose of the virus, but we are unlikely to notice.

Symptoms of both of these diseases are primarily mild, flu-like and likely to go undiagnosed. In extremely rare cases, it can be more severe and include encephalitis, but, to my knowledge, this has never occurred in Alaska. In fact, human infection itself is rare in this state, even among those who live in the arctic.

A virus-screening study that occurred in the Brooks Range community of Anaktuvuk Pass and the North Slope village of Kaktovik found low rates of infection. In Anaktuvuk, 21% of those surveyed had been exposed to Jamestown Canyon and only 2% had been exposed to Snowshoe Hare, while in Kaktovik a mere 5% showed exposure to Jamestown Canyon and none at all to Snowshoe Hare.

So, should a visitor to the arctic be concerned? Nope. At least not in my opinion. The plethora of mosquitoes during bug season will be enough motivation to keep you covered and well doused in bug dope, so you’ll naturally be taking the necessary precautions.

So, should a visitor to the arctic be concerned? Nope. At least not in my opinion. The plethora of mosquitoes during bug season will be enough motivation to keep you covered and well doused in bug dope, so you’ll naturally be taking the necessary precautions.

Besides, to experience the wildlife, beauty, and exquisite wildness of the arctic, I’ll gladly take the low risk of suffering “mild, flu-like symptoms”.

Wouldn’t you?

(If you are interested in learning more about viruses, the researchers that study them, and some that are much scarier than those in Alaska, you should check out David Quammen’s book “Spillover”. It’s a compelling read.)